diff --git a/lib/request.js b/lib/request.js
index 87b87dc..6300530 100644
--- a/lib/request.js
+++ b/lib/request.js
@@ -5,8 +5,8 @@
 
 var debug = require('debug')('koa:context');
 var qs = require('querystring');
+var typeis = require('type-is');
 var fresh = require('fresh');
-var mime = require('mime');
 var url = require('url');
 var parse = url.parse;
 var stringify = url.format;
@@ -486,38 +486,9 @@ module.exports = {
    */
 
   is: function(types){
-    // no request body
-    if (!(this.length || 'transfer-encoding' in this.header)) return;
-
-    var ct = this.type;
-    // no content-type
-    if (!ct) return false;
-
-    // paramless
-    ct = ct.split(';')[0];
-
-    if (!types) return ct;
-
-    // ensure array
+    if (!types) return typeis(this.req);
     if (!Array.isArray(types)) types = [].slice.call(arguments);
-
-    var mt;
-    for (var i = 0; i < types.length; i++) {
-      var type = types[i];
-
-      switch (type) {
-        case 'urlencoded':
-          mt = 'application/x-www-form-urlencoded';
-          break;
-        default:
-          mt = ~type.indexOf('/') ? type : mime.lookup(type);
-      }
-
-      if (mimeMatch(mt, ct)) return ct;
-    }
-
-    // no matches
-    return false;
+    return typeis(this.req, types);
   },
 
   /**
@@ -592,27 +563,4 @@ module.exports = {
       header: this.header
     }
   }
-};
-
-/**
- * Check if `exected` mime type
- * matches `actual` mime type with
- * wildcard support.
- *
- * @param {String} expected
- * @param {String} actual
- * @return {Boolean}
- * @api private
- */
-
-function mimeMatch(expected, actual) {
-  if (expected == actual) return true;
-
-  if (!~expected.indexOf('*')) return false;
-
-  actual = actual.split('/');
-  expected = expected.split('/');
-
-  if ('*' == expected[0] && expected[1] == actual[1]) return true;
-  if ('*' == expected[1] && expected[0] == actual[0]) return true;
-}
+};
\ No newline at end of file
diff --git a/package.json b/package.json
index 178ee12..69650bf 100644
--- a/package.json
+++ b/package.json
@@ -22,6 +22,7 @@
   "license": "MIT",
   "dependencies": {
     "accepts": "~1.0.0",
+    "type-is": "~1.0.0",
     "on-socket-error": "~1.0.1",
     "co": "~3.0.1",
     "debug": "*",
diff --git a/test/request/is.js b/test/request/is.js
index 057fd7e..415d9e5 100644
--- a/test/request/is.js
+++ b/test/request/is.js
@@ -49,8 +49,8 @@ describe('ctx.is(type)', function(){
       ctx.header['content-type'] = 'image/png';
       ctx.header['transfer-encoding'] = 'chunked';
 
-      ctx.is('png').should.equal('image/png');
-      ctx.is('.png').should.equal('image/png');
+      ctx.is('png').should.equal('png');
+      ctx.is('.png').should.equal('.png');
       ctx.is('image/png').should.equal('image/png');
       ctx.is('image/*').should.equal('image/png');
       ctx.is('*/png').should.equal('image/png');
@@ -69,8 +69,8 @@ describe('ctx.is(type)', function(){
       ctx.header['content-type'] = 'image/png';
       ctx.header['transfer-encoding'] = 'chunked';
 
-      ctx.is('png').should.equal('image/png');
-      ctx.is('.png').should.equal('image/png');
+      ctx.is('png').should.equal('png');
+      ctx.is('.png').should.equal('.png');
       ctx.is('text/*', 'image/*').should.equal('image/png');
       ctx.is('image/*', 'text/*').should.equal('image/png');
       ctx.is('image/*', 'image/png').should.equal('image/png');
@@ -89,9 +89,9 @@ describe('ctx.is(type)', function(){
       ctx.header['content-type'] = 'application/x-www-form-urlencoded';
       ctx.header['transfer-encoding'] = 'chunked';
 
-      ctx.is('urlencoded').should.equal('application/x-www-form-urlencoded');
-      ctx.is('json', 'urlencoded').should.equal('application/x-www-form-urlencoded');
-      ctx.is('urlencoded', 'json').should.equal('application/x-www-form-urlencoded');
+      ctx.is('urlencoded').should.equal('urlencoded');
+      ctx.is('json', 'urlencoded').should.equal('urlencoded');
+      ctx.is('urlencoded', 'json').should.equal('urlencoded');
     })
   })
 })
\ No newline at end of file